The present invention relates to the field of sensors which are attached to a subject to be monitored, particularly a sensor which is attached with adhesive to the subject. The preferred embodiment of the present invention is directed to the field of sensors for use with pulse oximeters.
The present invention provides a means of improving the durability of a sensor, particularly a sensor which is attached with adhesive to the subject which is to be monitored. The preferred embodiment-of the present invention is directed to improving the durability of sensors which are connected to pulse oximeters.
A pulse oximeter is a device which monitors the oxygen content of the blood of a subject by measuring the blood""s absorption of light. The sensor includes a pair of light emitting diodes (L.E.D.) and a photocell detector which are coupled to wires connected to the pulse oximeter. The diodes, the detector, and a portion of the wires are covered with a flexible casing made of plastic and paper. An adhesive material is typically coupled to the casing.
When in use, the casing is wrapped around a part of the subject, typically a finger. When properly applied, the diodes are aligned on the subject so that they are facing the photocell detector with the subject""s finger in between. The sensor is held in this position by affixing it to the skin with the adhesive material.
A known problem with the sensors described above is the limited lifespan of the adhesive and the lack of durability of the casing.
In addition, maintaining the cleanliness of the sensor is desirable since the casing touches the skin of the subject directly. However, the ability to clean the sensor is limited in that the adhesive portion of the sensor is permanently coupled to the casing. The adhesive portion cannot be conveniently cleaned without adversely affecting the strength of the remaining adhesive.
Another motivation for making such cleaning possible is to maintain the accuracy of the sensor. A study has shown that a build up of adhesive on the diodes may cause inaccurate readings by the pulse oximeter. Inaccurate readings on a medical instrument are clearly undesirable and potentially dangerous. The ability to clean the diodes and detector would provide a means to avoid this potential source of inaccuracy, potentially increasing patient safety.
It is an object of the present invention to increase the durability of a sensor.
It is a further object of the present invention to make convenient cleaning of a sensor possible without adversely affecting the function of the sensor.
It is another object of the present invention to improve the cleanliness of a sensor by providing a dedicated means of attaching the sensor to the subject.
It is yet a further object of the present invention to provide a uniform size shield to protect and affix a variety of sensors of potentially different sizes.
It also an object of the present invention to provide all of the above objects without adversely affecting the performance of the sensor during use.
The method of the present invention involves laminating the casing of the sensor to increase its durability. The lamination material includes two apertures; one to accommodate the diodes and one to accommodate the detector.
The laminated casing may then be inserted into a disposable shield which includes an adhesive strip. The shield protects the casing of the sensor from direct contact with the subject""s skin. In the preferred embodiment, the shape of the shield is well suited to the proper mounting of the sensor on the subject""s finger. However, the shield may be of other shapes and configurations to facilitate mounting on a toe or some other extremity, as appropriate.
The use of the present invention permits the laminated casing to be easily removed from the shield and the shield to be discarded. The laminated casing may be cleaned and inserted into a new clean shield for use. In this way, conditions that may have previously been cause for discarding the sensor are now only cause for discarding the shield. Examples of such occurrences are contamination of the shield, loss of adhesion of the adhesive, tearing or other damage to the adhesive material portion.
The foregoing and other objects features and advantages of the present invention will be apparent from the following, more particular description of the preferred embodiment of the invention and as illustrated in the accompanying drawings.